The Batch server limits the maximum number of jobs that can run simultaneously. This defaults to 5. To modify this setting, change the <Value> entry in the “Max Concurrent Jobs” option in the <BatchServerOptions> section. (Note that the actual number of concurrent processes is also restricted by memory.)
<BatchServerOptions>
…
<Option>
<Name>Max Concurrent Jobs</Name>
<Value>5</Value>
</Option>
…
</BatchServerOptions>